Bivalent metal halide addition compounds of substituted sulfenamides



Patented Jan. 8, 1952 UNITED OFFICE BIVALENT 7 HALIDE ADDITION.

COMPOUNDS F FjSUBSTITU'I'ED :SUL-

FENAM'IDES.

Edward L. Carr, Akron, Ohio, and John Richard Rafter, Bristol Ferry, R.1., assignors to The FirestonrTire '& Rubber Company,v Akron,

Ohio, a corporation onomo No Drawingo. Application July,9,n194'9,,SerialNo. 103,946 v 17 Claims. (clicsmeaat in which R; R, and R",'whichmay all be the same or different, are hydrogen or a hydrocarbon III alyl (including hydrocarbon cycloalkyl), hy: drocarbon aryl or hydrocarbonaralkyl substituent or furfuryl or tetrahydrofurfuryl or NRR" may be ahetorocyclic group in which RR is alkylene or alkylene-oxy-alkylene asin diethylene-. oxy, as for example, piperidyl, morpholy-l',-'etci.; Ris a hydrocarbon alkyl (including hydrocara bon cycloalkyl) hydrocarbonaryl or hydrocarbon aralkyl substituent or furfuryl or tetrahydrofurandin Formula III the R" and R" mayjoin with the nitrogen to form aheterocyolicgroup in:

which R"R"' is alkylene or alkyleneeoxy-alkylene, such as piperidyl,morpholyl, etc The subscript n is 1 or 2.

Typical compounds are the zinc chloride, etc., addition compounds of:

N-furfuryl thiazoline sulfenamide N -methyl thiazoline sulfenamideN,N-diethyl thiazoline sulfenamide -N-cyclohexyl thiazoline sulfenamideN-cyclohexyl l-methyl thiazoline sulfenamide N -cyclohexyl-4,5-dimethylthiazole sulfe'namlde N-isopropyl-e-5 dimethy1 thlazole' =sul ienamlde N-cyclohexyl bethyl thiazole sulfenamide N-ethyl-4-ethyl thiazolesulfenamide N,N-diethyl-4,'5-dimethyl thiazole sulfenamide N,N-ditetrahydrofurfuryl thiazole sulfenamideN,N-diethyl.diethylthiocarbamyl sulfenamide N cyclopentamethylenecyclopentamethylene thiocarbamyl sulfenamide N -cyclo hexyl Idimethylthiocarbamyl sulfenamide N,N-dlcyclohexyl naphthothiazolesulfenamide N-eisopropyl henzothiazole sulfenamide N- yolohexyl .benzohia ole I s lfenamide N -methyl benzothiazole .sulfenamide N, ll.-'ditetrahydrofurfuryl ditetrahydrofurfuryl hio arbamyl sul e amideEach of *the-above-mentioned sulfenamides may be produced-by any of theusual sulfenamid'e preparation-reactions which employ water-solubl'eamines;- However, the invention is not limited-to.suchsulfenamides butincludes the additionproducts of. all sulfenamidesrsuitable for usein.p;l-ast;ics Sulfenamides produced. .from insoluble aminea-suflh assulienamides with aromatic substituents long-chain aliphaticsubstituents, etc., may be produced by metathesis. For example, N-dodecyl benzothiazole sulfenamide may beproduced by dissolving,benzothiazole sulfena- ,mide in .dodscyl amine and. allowing themixture too-stand until the reaction has taken place. Similarly, N-phenyl fthiazoline sulfenamide, V N -tolyl thia zole sulfenamide', andN-phenyl dimethyl- 'thiocarbamyl"sulfenamide are illustrative ofarylsubstituted compounds formed in this manner, from which-metal-halidecomplexes of this invention may be formed.

In addition to the sulfenamide vulcanization accelerators" mentionedabove; other known sulienamideaccelerators which are "suitable forpreparation of the metal halide addition compounds of the inventionaredisclosed in'the following United States patents: 2,271,834, 2,339,552,2,367',82'Z,2 ,381,384', 2381;392' and 2,445,722.

The zinc chloride addition productsare accelerators'ofthe vulcanizationlot natural rubber. Theformation of the complex permits converting alow-melting 'or liquid sulfenamide, which is often unstable,- into ahigher-melting or solid compound; :thus' rendering the accelerator morestable or ,more easily handled. The addition products give a slower curethan the sulfenamides fromwh-ich they are formed and are delayed-action"aee1erawrs.- The 'vulcanizjed products" are different from thoseproducedwith the sulfena mides.

I compounds give a lower modulus natural rubber stockthan anequaI weightof the parent sulfena- For instance, the zinc chloride addition saltsmay be used in curing rubber and rubberlike materials.

The following examples are typical, andillustrate the preparation andcharacterization of representative metal halide addition compounds ofthe invention.

Example 1 An ether solution of N-cyclohexyl benzothiazole sulfenamidewas mixed with an ether solution of zinc chloride.

yield of the addition product or salt, which was a white, granularsolid, M. P. 150 160 C'. This product had the formula:

Y 1 'Parts Smoked sheet 1- Sulfur 3- Zinc oxide 5 Stearic acid .1.10Accelerator 0.75

The stocks were cured at two different temperatures for varying lengthsof time. The time is expressed in minutes in the following table,whichgives the modulus and tensile strength for the control and the testmaterial in pounds per square inch: 7

The proportion of reactants was 2 moles sulfenamide to 1 mole zincchloride. Im-

mediate reaction occurred giving a quantitative Y standing for one weekthe reaction mixture was 100 cc. of ethyl alcohol to form a dark green,clear solution. Fifty-three grams of N-cyclohexyl benzothiazolesulfenamide were dissolved in 700 cc. of ethyl alcohol to which wasadded 100' cc. of benzene. The two solutions were mixed and themixtureimmediately became dark in color; after a few minutes achocolate-brown solid separated out. The solid was washed twice withether. Themelting point of the product,

10 N-cyclohexyl benzothiazole sulfenamide cupric chloride, was 160 0.

Example 3 To 56 grams (0.25 mole) of N-isopropyl ben- 1 zothiazolesulfenamide (M. P. 97-99 C.) dissolved in 700 ml. of absolute ethylalcohol there was added slowly l'lgrams (0.125 mole) of U. S. P. zincchloride dissolved in 100 ml. of ethyl alcohol. Precipitation wasevident in 24 hours. After filtered with suction. The white residue wasground under ether, filtered and dried at room temperature in vacuo. Theyield of product was 19.5 grams, melting at 183 C. On analysis the 5product was found to contain 11.5% of zinc,

agreeing with 11.2% of zinc calculated from the following formula:

NHCHCHs Eaxample 4 3 5 Fifty-six grams (0.25 mole) of N-isopropylbenzothiazole sulfena-mide and 16.8 grams (0.125 mole) of reagent gradeanhydrous cupric chloride were reacted in accordance with the procedureof Example 3. A green-brown precipitate 49 immediately formed, and thisproduct was sepamelt below 360 C. Calculated for copper: 17.8%

600% Modulus Tensile at Breal:

Cured at 240 F.:

Control 750 1, 800 Test material 375 Cured at 280 F.:

ConiIOl 2, 500 2, 300 1, 825 3, 725 3, 675 Test material 1, 350 1, 525l, 300 3, 550 3, 250

i The above results show that the zinc chloride addition compoundaffects the modulus: more than the tensile strength and'servesto preventthe stock from curing too stiff. Y

The zinc chloride salt of N-cyclopentamethyl-' ene cyclopentameth'ylenethiocarbamyl "sulfen-t CHzCfiz omen! 2 For the preparation of cupricsalts, some other solventthan ether will be preferred, as, for; (2X1:

p e, ethyl alcohol. i i V Example -2 1 (when n in the formula'is 1) and10.9% (when n in the formula is 2). Found: 14.1% copper, indicating thatthe product was a mixture of the two addition compounds. The product wasthen washed with hot toluene and dried. This purified product behavedthe same as the original product upon heating (it did not melt under 360C.) but analysis showed it to contain 16.7% of copper indicating that itconsisted largely of the L following compound:

' f@ C NHCHOH; .(JuCh V L ta. i

Example 5 The addition compound of Example 1 was. again prepared,lnaking use of purer reagents,

: SevePte-n ems.es a ate.re .ies r leilla f al.z i -szy lohe yl.benzo io e. su

ed largely ofz semantics Example 6 N+ y 10h Xy1-N',NEdi thyL,--thiocanbamyl sul- .fenamide was recrystallized;fromrlowaboiling pe-ywtroleum' 1e;ther-;.-.,to;,-aL-" c nstantZ meltin iIlOiHtQiOf 67-68 C. To61.5 grams (0.25 molehsoirthezpure ,sul-fenamide dissolvedg1inzfz25flimlz; anhydrous re-thyl ether there;wagslowlybadded with: stirri ng,-.acleari 100 ;;m1v=;ether solutiorr icontainin 17.0 grams (0.125 mole).ofz;zinc;z:chloride.'-;'g Ihe -iprecipit ter which; :torme .tmedia.moyed.--;.,by..-gfiltration and, ,=crude. product was o ai-ned. n,

rg-ramspmelting at, 1-1.2-; l;1;5, 'C. ter :re'crystal :lization from. amixture; iofirohloroformlandizlow 1 boiling =petro1eum-= ,ether the:- oduct::-.meltedr:'at 116-118 C. and wasgfound; by analysismzcon- .tain10.0 v-of zinc, agreeing w h,,.;A-%; oti'zinc -.-c,alculat,ed from.;.-the followingformular .g-IIo amethylalsolution:QLNecycIohexyI-NQNdiethyl thiocarbamyl sulfenamide therewvas iaddwed; a-zlc-lear,green;methylal-rsolutiomof; cupric chloride. A greensolid'zprecipitatedsimmediately (Weight 17.6.;grams; M? P5-i94=e95 C.),which was recrystallizedfiromlmethanoiepetroleum ether to give thepurified product, meltin at 95-96" C. Calculated for-icopperxd-when niin the formula is 1) 16.7%; found by analysis 16.4%.

Example 8 N,N-diethyl benzothiazole sulfenamide is a liquid whichdecomposes upon standing at room temperature. This sulfenamide wasreacted with zinc chloride in accordance with the procedure of Example 8to produce an addition compound melting at 131-134 C. When the reactionwas carried out in a methylal solution (instead 01 by filtratiqn washedwith .ethylether .and .;dried. ilihe addition, compound, .so-prepared,melted. ,at 170?; C.

in ether) a;sgizeem:additiomcompoundcwas obtained, meltin at 214-216 C.

'1. Example 10 N-cyclotetramethylene 2--e-tetrahydrobenzothiazole sulfenamide.is.v a =liquidi-whichtdecomposeS- up n-.standing. To aneether.solution. con- .,taining 1.0; gram. (0.004. ;mole). of this-1, sulfen-,amideythere. was slowly added; withstirr-lngi. an v c .t 1y1etherrtetrahydrofuran.solution. containing 0.5%,,gram (0004f mole) ,oianhydrous zinc ch10- ride. ..'(The.;zinc,,chloride.,solutiona wasprepared -.by,...,dissolving.the; .-.sa1t ,in a minimum,-quantity of-v.tetrahydrofuran.,and 1 diluting with ethyl ether.) iiThe resulting.precipitate: was removed sulfenamide (Ms P2 68-70 C.) in anhydrous ethylether lthere wasi add'ed a' saturated solution- 0f a anhydrous. zincchloride in: anhydrous ethy1 x-r'ether. The zresulting precipitatewascseparated fromthe -.-'reactionsolution and recrystallized -f-rom"chloroform-lows boilirig petroleum ether.

The crystalline product melted jat 88=90? C. =Analysis showedthe:product to-vcontains% of zinc, indicating ,the following: structure:

.1 Thus. it.=is-,seen..that-. thezaddition compounds of the,inventionare always highenmeltingaand h therefore.-more stabletand ,more easilyhandled, tthanthe .correspondingsul-fenamidesriromfwhich theyareprepared. The compoundseofztheinyen- .tion, are delayed-action rubbervulcanization acg .celerators. and mayhavecommercial .yalue-, .also

as fungicides .and, .insecticides,1 vas .well, as other USES.

.'Ihis., -app1ication is; ay-ucontinuationeinepart. of our copendingapplication Serial No. .--:.5.3,85 8,

filed-March, 20, 1945,..now; Patent :No; 2,476,818.

. What .we claim. is:

g mpQ -m s avipgrtheeiormula where R is selected from the group ofradicals consisting of hydrogen, hydrocarbon alkyl, hydrocarbon aryl,hydrocarbon aralkyl, furfuryl and tetrahydrofurfuryl, R is selected fromthe goup of radicals consisting of hydrogen, hydrocarbon alkyl,hydrocarbon aryl, hydrocarbon aralkyl, furfuryl and tetrahydrofurfuryl,also where NRR is a heterocyclic radical in which RR is selected fromthe group consisting of alkylene and alkylene-oxy-alkylene, R isselected from the group of radicals consisting of hydrogen, hydrocarbonalkyl, hydrocarbon aryl, hydrocarbon aralkyl, furfuryl andtetrahydrofurfuryl, MX2 is a complex-forming salt in which M is abivalent metal of the group consisting of zinc, copper and cadmium and Xis a halide radical of the class consisting of chlorine, bromine and 10-dine, and -n is selected from the group consisting of 1 and 2. A

't 2. Compounds having the formula where R is selected from the group ofradicals consisting of hydrogen, hydrocarbon alkyl hycarbon alkyl,hydrocarbon aryl, hydrocarbon aralkyl, furfuryl and tetrahydrofurfuryl,also where NRR is a heterocyclic radical in which RR is selected fromthe group consisting of alkylene and alkylene oxy-alkylene, R" isselected .from the group of radicals consisting of hydromine and iodine,and n is selected from the group consisting of 1 and 2.,

3. Compounds having the formula in which R is selected from the group ofradicals consisting of hydrogen, hydrocarbon alkyl, hydrocarbon aryl,hydrocarbon aralkyl, furfuryl and tetrahydrofurfuryl, R is selected fromthe goup of radicals consisting of hydrogen, hydrocarbon alkyl,hydrocarbon aryl, hydrocarbon aralkyl, furfuryl and tetrahydrofurfuryl,also where'NRR' is a heterocyclic radical in which RR is selected fromthe group consisting of alkylene and alkylene-oxy-alkylene, R isselected from the group of radicals consisting of hydrogen, hydrocarbonalky l, hydrocarbon aryl, hydrocarbon aralkyl, furfuryl andtetrahydrofurfuryl, R' is selected from the group of radicals consistingof hydrocarbon alkyl, hydrocarbon aryl, hydrocarbon aralkyl, furfuryland tetrahydrofurfuryl, also where NRR"' is a heterocyclic radical inwhich R"R"' is selected from the group consisting of alkylene andalkylene-oxyalkylene, MXz is a complex-forming salt in which M is abivalent metal of the group consisting of zinc, copper and cadmium and Xis a halide radical of the class consisting of chlorine, bromine andiodine-,ratnd n isselected from the group consisting-oil and 2;

4. An addition compound 01 (1) a halide of a bivalent metal of the groupconsisting of zinc, copper and cadmium and (2) a sulfenamide of thegroup consisting of thiazole sulfenamides, thiazoline sulfenamides andthiocarbamyl sulfenamides', said sulfenamide being an accelerator ofrubber vulcanization.

' 5. N-cyclohexyl-N',N-diethy1 thiocarbamyl I sulfenamide zinc chloride.

' 6. N-cyclohexyl benzothiazole sulfenamide zinc chloride.

7. N,N-diethyl benzothiazole sulfenamide zinc chloride. 8. A bivalentmetal halide addition compound of a sulfenamide of the group consistingof a thiazole sulfenamide, a thiazoline sulfenamide and a thiocarbamylsulfenamide, said metal beingselected from the group consisting of zinc,copper and cadmium.

9. A zinc chloride addition compound of a thiazole sulfenamide.

10. A bivalent metal halide addition compound of a thiazolinesulfenamide, said metal being selected from the group consisting ofzinc, copper and cadmium.

' 11. A bivalent metal halide addition compound of a thiocarbamylsulfenamide, said metal being selected from the group consisting ofzinc, copper and cadmium.

12. The method of making an addition com pound which comprises reactinga bivalent metal halide and a sulfenamide of the group consisting of athiazole sulfenamide, a thiazoline sulfenamide and a thiocarbamylsulfenamide, said metal being selected from the group consisting ofzinc, copper and cadmium.

13. The method of claim 12 in which the reaction is carried out in thepresence of a solvent.

14. The methodof claim 12 in which the reaction is carried out in thepresence of a solvent for the sulfenamide.

15. The method of claim 12 in which the reaction is carried out in thepresence of a solvent for the bivalent metal halide.

16. N-cyclohexyl-2-thiazoline sulfenamide zinc chloride.

" 1'7. N-cyclohexyl-N'.N-diethyl thiocarbamyl sulfenamide cupricchloride.

' 3 EDWARD L. CARR.

JOHN RICHARD RAFI'ER.

. No references cited.

1. COMPOUNDS HAVING THE FORMULA